A rapid growth of the wireless mobile communication market leads to various multimedia services in a wireless environment. To provide various multimedia services, recent researches have been conducted on communication schemes for transmitting data at a high data rate. For example, an Orthogonal Frequency Division Multiplexing (OFDM) communication scheme is being developed.
Using the OFDM scheme, the wireless communication system enables a high-speed data transmission beyond multiple delays of the channel by dividing a wide frequency band into a plurality of narrow bands.
Using the OFDM scheme, the wireless communication system allocates resource such that one user occupies one narrow band.
To raise frequency utilization, the wireless communication system may adopt an Orthogonal Frequency Division Multiple Access (OFDMA) scheme which lets a plurality of users to divide and use one narrow band.
Using the OFDMA scheme, the wireless communication system can maximize a multi-user diversity gain by allocating the frequency band on a user basis.
Accordingly, a base station of the OFDMA wireless communication system schedules in consideration of the multi-user diversity gain. For the scheduling based on the multi-user diversity gain, the base station requires instantaneous channel information of terminals in its service area. For doing so, the terminals send their instantaneous channel information to the base station over an uplink feedback channel.
Since the wireless communication system is subject to the limited radio resources, the uplink feedback channels allocated from the base station to the terminals act as an overhead onto the wireless communication system.
As the number of the serviced terminals increases in the wireless communication system, the amount of the feedback channels allocated to the terminals also increases. As a result, the overhead due to the feedback channels further increases.